This invention generally relates to percutaneous leads for performing one or more of mapping pacing, or ablation, the percutaneous lead being particularly well suited for performing these functions in association with the treatment of cardiac conditions, and it lends itself particularly well for use as a disposable, temporary treatment device.
While the lead is substantially isodiametric when it is being passed through a narrow body passageway such as a vein or an artery, the distal end portion of the percutaneous lead preferably includes a plurality of elongated slits that are spaced from each other around the circumference of the distal end portion in order to define at least one elongated peripheral segment having an electrode, which elongated peripheral segment is adjustable to the extent that it folds substantially upon itself in order to generally radially move its electrode outwardly. This adjustability feature of the device is such that the elongated slit and its electrode are readily returned to an orientation that is substantially isodiametric with the remainder of the percutaneous lead. When desired, a plurality of such adjustable elongated peripheral segments are provided.
Electrophysiological studies and treatments of patients have in the past utilized many different devices and systems, including those that incorporate the use of an elongated percutaneous lead that provides an electrically conductive elongated pathway between a location that is external of the patient and a location within the patient at which sensing, stimulation or treatment is to take place. When this percutaneous route is taken in conjunction with studies or treatment of the heart, this is known as an endocardial approach. While an epicardial approach is possible, this is not always the most suitable procedure since it requires thoracotomy and the exposure of the heart.
When the study or treatment to be performed includes mapping and/or ablation, such procedures require accurate identification of the focus or foci by recording the electrical signals generated by the cardiac tissue at specific locations. Once identified, each focus is ablated or fulgurated. It is highly desireable, if not mandatory, to ablate the abnormal source in an accurately circumscribed location in order to minimize damage to normal tissue that is adjacent to the area of the anomalous tissue. Often, such accurate location is substantially enhanced when the epicardial approach is used rather then the substantially less intrusive endocardial approach.
Accordingly, there is a need for a device that has the attributes of the less intrusive endocardial approach while still providing substantial control and adjustability on the order of that possible by the epicardial approach so that the endocardial approach is more feasible for studies and treatments including those involving any or all of mapping, destruction, or pacing functions.
With more particular reference to these functions, the pacing function is well-known in the art, whereby an electrical impulse is imparted to a particular location of the body in order to either assist proper functioning of a body organ or in order to control or bring under control an iatrogenic or spontaneous dysrhythmia by pacing a ventrical or in order to stimulate or pace the heart so as to assist in mapping its electrical pathways. Currently available so-called pacing leads can accomplish these functions in an endocardial manner by receiving appropriate impulses from a pacer device that is external of the body. Typically, these devices are capable of performing only this pacing function.
Regarding the mapping function, such is undertaken to identify specific foci or anatomical locations which, for example, are a source of abnormal cardiac rhythm in patients with dysrhythmias. Mapping electrode sets for epicardial or endocardial mapping of heart signals have been provided in the past. Typically, these mapping electrode sets are utilized during cardiac surgery in order to sense the cardiac signal and report it to the surgical team through appropriate display and/or print out devices. The surgical team may observe the reported data and immediately utilize same in connection with a surgical procedure, or the data may be collected for subsequent analysis. Such mapping involves timing that is based upon the leading edge of an excitation wave through conductive tissue, such as that of the heart. Generally, mapping procedures include the induction of tachycardia while the mapping electrode set is in place, which means that mapping speed and efficiency are important during these procedures.
The ablation function is typically performed in association with the mapping function. Once the specific foci or anatomical locations are pinpointed by mapping or the like, each such location can be subjected to ablation or fulguration in order to, in effect, destroy the target focus or location, which for example, is the source of an abnormal cardiac rhythm. Unless the ablation function is carried out in close association with the mapping function, it is exceedingly difficult to achieve the ablation accuracy which is necessary to avoid or minimize damage to normal or undiseased tissue that is adjacent to the anomalous, damaged or diseased tissue to be destroyed by the ablation procedure.
When one attempts to carry out the mapping function and/or the ablation function by an endocardial approach, mapping accuracy, speed and efficiency are typically quite difficult to achieve since the mapping device must pass through a narrow body passageway such as a vein or an artery. Often, electrodes of a device for carrying out endocardial mapping provide mapping electrodes that are generally stationarily mounted with respect to each other, whereby it is difficult to substantially modify the mapping surface, a situation that is further complicated by the requirement of fluoroscopic guidance for placement of mapping electrodes and, for that matter, of the ablation tip of an endocardial ablation device or catheter.
Another exceptionally desirable feature for a mapping device is to provide it with an electrode array by which the electrodes of the array can simultaneously engage the surface being mapped. When the endocardial approach is undertaken, the surfaces being mapped usually will be concave or generally flat. Unless the electrodes of the mapping electrode set exhibit some degree of adjustability, it is not possible to have the same device map such a variety of surface configurations. This type of adjustability is rendered more difficult when such must be provided for an endocardial device which, ideally, should be substantially isodiametric throughout the length of the device.
There is accordingly a need for a device that can achieve endocardial mapping or other percutaneous procedures, which device is a substantially isodiametric catheter-type of device that has a distal end portion having an electrode that is location-adjustable when the device is at or near its percutaneous target location, which adjustment is carried out by manipulation of a suitable assembly that is external of the body.
These various desirable attributes are achieved by the present invention, which provides a percutaneous lead having an elongated body and an elongated shaft slideably mounted within the body, with the respective distal end portions of the elongated body and of the elongated shaft being operatively connected to each other. The distal end portion of the elongated body is substantially isodiametric with the rest of the body and has a plurality of elongated slits that are spaced from each other along the circumference of the distal end portion of the body in order to define at least one elongated peripheral segment of the body distal end portion. An electrode is positioned on the elongated peripheral segment. When the elongated body and/or the elongated shaft are slidingly moved with respect to the other, which relative movement includes either or both of movement of the body in a distal direction or movement of the shaft in a proximal direction, the elongated peripheral segment generally folds onto itself in a substantially outwardly directed manner to thereby move the electrode thereof to a location that is no longer isodiametric with respect to the elongated body. Relative movement of the elongated body and/or elongated shaft in substantially opposite directions returns the elongated peripheral segment and its electrode to its initial, substantially isodiametric configuration.
It is accordingly a general object of the present invention to provide an improved percutaneous lead that exhibits adjustability between isodiametric and outwardly extending electrode configurations.
Another object of the present invention is to provide an improved percutaneous lead that is capable of performing mapping, ablation and/or pacing without having to remove the lead from its percutaneous location.
Another object of this invention is to provide an improved percutaneous lead that functions in the manner of an endocardial catheter that can be guided through a narrow body passageway such as a vein or an artery when it has a substantially isodiametric configuration but which can, after it has been properly positioned within the body, be manipulated such that distal electrodes thereof expand radially outwardly.
Another object of this invention is to provide a torque-controlled temporary pervenous lead having recording electrodes for mapping of endocardial electrophysiological signals, having electrodes for unipolar or bypolar pacing, and having ablating capabilities.
Another object of the present invention is to provide an endocardial lead having a multiple electrode array for mapping plane or concave internal surfaces.
Another object of this invention is to provide an endocardial mapping lead that has an electrode array for precise location of the ablation electrodes and by also recording from a central or tip electrode in order to permit identification of excitation propagation.
Another object of this invention is to provide an improved percutaneous lead that is a relatively inexpensive and disposable.
Another object of the present invention is to provide an improved percutaneous lead having laser-conducted ablation.
These and other objects, features and advantages of this invention will be clearly understood through a consideration of the following detailed description.